var events = require('events');
var eventEmitter = new events.EventEmitter();
var connectHandler = function connected() {
    console.log('连接成功...');
    eventEmitter.emit('data_received');
}

eventEmitter.on('connection', connectHandler);
eventEmitter.on('data_received', function () {
    console.log('数据接收成功...');
});

eventEmitter.emit('connection');
console.log('程序执行完毕');